Personal prescription drug importation occurs in the United States because of the high cost of U.S. medicines and lower cost of foreign equivalents. Importation carries a risk of exposure to counterfeit (i.e., falsified, fraudulent), adulterated, and substandard drugs. Inadequate health insurance may increase the risk of importation. We use inverse probability weighted marginal structural models and data on 87,494 individuals from the 2011-2013 National Health Interview Survey to estimate the marginal association between no health insurance and importation within U.S. subpopulations. The marginal prevalence difference [95% confidence limits] for those without (prevalence = 0.031) versus those with health insurance was 0.016 [0.011, 0.021]. The prevalence difference was higher among persons who were Hispanic, born in Latin America, Russia, or Europe, traveled to developing countries, and did not use the Internet to fill prescriptions or to find health information. Health insurance coverage may effectively reduce importation, especially among particular subpopulations.